As a type of electrophotographic photosensitive members used in electrophotographic apparatus, an electrophotographic photosensitive member is widely known which has a photoconductive layer (photosensitive layer) made up of amorphous silicon and a surface layer provided on the photoconductive layer and made up of hydrogenated amorphous silicon carbide. The photoconductive layer made up of amorphous silicon and the surface layer made up of hydrogenated amorphous silicon carbide are formed by, e.g., a film forming technique such as plasma CVD. Hereinafter, the amorphous silicon is also termed as “a-Si”, the photoconductive layer made up of a-Si is also termed as “a-Si photoconductive layer”, and the electrophotographic photosensitive member having such an a-Si photoconductive layer is also termed as “a-Si photographic photosensitive member”. The hydrogenated amorphous silicon carbide is also termed as “a-SiC”, and the surface layer made up of a-SiC is also termed as “a-SiC surface layer”.
Regarding such an a-Si photographic photosensitive member, it has been studied to provide between the a-Si photoconductive layer and the a-SiC surface layer an intermediate layer made up of a-SiC (Japanese Patent Applications Laid-open No. 2005-301233 and No. S61-159657). Such an intermediate layer is provided for various purposes of, e.g., preventing interference of the light that reflects from the surface of the surface layer with the light that reflects at an interface between the surface layer and the photoconductive layer, and improving delamination resistance (adherence) between the photoconductive layer and the surface layer. In some cases, it is provided not only as a single layer but also as a plurality of intermediate layers. An intermediate layer made up of a-SiC is hereinafter also termed as “a-SiC intermediate layer”.
In spite of such an a-Si photographic photosensitive member having been so far studied and improved as above, in the present state of affairs, there still remains room for further improvement from the viewpoint of making electrophotographic process higher in speed and higher in image quality in recent years.
For example, as the electrophotographic process is made higher in speed, the electrophotographic apparatus becomes higher in process speed, where, e.g., a cleaning blade may chatter to tend to cause slip-through of a toner (developer). As a countermeasure therefor, a method is available in which the cleaning blade is pressed against the electrophotographic photosensitive member at a higher pressure.
However, studies made by the present inventors have revealed that, where a plurality of a-SiC intermediate layers are provided between the a-Si photoconductive layer and the a-SiC surface layer, the a-SiC intermediate layers more tend to come to separate between their layers with an increase in the pressure at which the cleaning blade is pressed against the electrophotographic photosensitive member. This is because such an increase in the pressure at which the cleaning blade is pressed against the electrophotographic photosensitive member makes stress concentrate at an interface(s) between layers of the a-SiC intermediate layers provided in plurality between the a-Si photoconductive layer and the a-SiC surface layer, as so considered.